1. Field of the General Inventive Concept
The present general inventive concept relates to a non-volatile memory device.
2. Description of the Related Art
In order to satisfy consumer requirements, including, for example, high performance and low cost, there is growing demand for high density semiconductor memory device in the development of semiconductor fabrication techniques. Since the integration density of a semiconductor memory device is important factor in pricing the semiconductor memory device, increased integration density is particularly required. In a conventional two-dimensional (2D) or planar semiconductor memory device, the integration density is mainly determined by an area occupied by a unit memory cell. Thus, the conventional 2D semiconductor memory device is greatly affected by micro-patterning technologies.
However, very expensive equipments are required to achieve micro-patterning, the conventional 2D semiconductor memory device still has limitation in increasing the integration density.
In order to overcome the limitation, a vertical cell string structure is being researched, in which memory cells are formed in a three-dimensional manner.
In the vertically stacked non-volatile memory device, it is necessary to prevent leakage of charges stored in a charge storage layer and to improve the reliability of the memory device.